Applied Physics Seminar
Abstract:
Industrial carbon capture will deliver substantive climate benefit only when the sequestered CO₂ is converted into products of high economic value. In the first part of this seminar, I will describe how my group transcends conventional electrochemical CO₂ reduction—whose low-molecular-weight products (CO, formate, ethylene) command limited margins and incur significant separation costs—by engineering redox-neutral reaction networks that intrinsically couple oxidation and reduction steps. Incorporating reversible charge shuttles within the catalyst layer closes the electron balance, continuously regenerates active sites, and allows operation in undivided cells at ambient temperature. This approach enables the direct electrosynthesis of dimethyl and diethyl carbonate from CO₂ and alcohols with Faradaic efficiencies up to 60 % and underpins a modular aqueous reactor that captures CO₂ as bicarbonate, co-produces H₂, and upgrades the carbon into ethylene carbonate at costs competitive with established petrochemical routes. I will present mechanistic insights from operando spectroscopy, scale-up metrics drawn from techno-economic analyses, and the design principles that render redox neutrality a broadly applicable paradigm for carbon-to-chemicals platforms.
For the final ten minutes, I will pivot to a complementary frontier in nanoscience: peptide-directed synthesis of chiral plasmonic nanoparticles. Chiral peptides adsorb enantioselectively on high-Miller-index facets of growing gold crystals, thereby breaking mirror symmetry and producing 432-symmetric morphologies that exhibit record optical dissymmetry factors. I will outline how these biologically encoded nanostructures enhance light–matter interactions and open new avenues in enantioselective sensing, photonics, and asymmetric catalysis.
Taken together, these two vignettes underscore a unifying theme: coupling chemical or biological cycles provides a powerful strategy for unlocking functionalities—and real-world impact—that single-step processes cannot achieve.
More about the Speaker:
Professor Ki Tae Nam received his B.S. and M.S. in Materials Science and Engineering from Seoul National University, and his Ph.D. in Materials Science and Engineering from MIT. He got the "outstanding PhD thesis award" from MIT. His PhD thesis was about the "virus-based battery" that has been highlighted as the first demonstration of virus based electrochemical devices. During his postdoc (2007-2010) at Lawrence Berkeley National Lab, he studied peptide mimetic polymer to assemble two dimensional structures. Since 2010, His group at SNU continue to pioneer the research area of bioinspired material science to make new functional materials for energy and optical applications. Recent innovations include the development of CO2 utilization chemistry (Nature Energy. 2021, 6, 733 and Nature synthesis. 2024, 3 etc) and the peptide based synthesis of chiral nanomaterials (Nature 2018, Nature 2022 and Nature Materials 2024). In 2022, He received the POSCO Chung-am Award that is one of the most prestigious award in Korea. He serves as an associate editor for Nano Letters.